Industrial truck



Nov. 10, 1942. s. K. TowsoN ETAL INDUSTRIAL TRUCK Filed Oct. 30, 1940 6 Sheets-Sheet l INV EN I'OR.5

Nov. 10, 1942.

S. K. TOWSON ET AL INDUSTRIAL TRUCK Filed OCT.. 50, 1940 6 Sheets-Sheet 2 (D l l l O 'L l :V: Vfrf I l l i 1 'r- 11i INTORS SHEL 00N K TOM/50N BY 62 mi Cow/MM #Ma/MMM ATTORNEYS.

Nov. l0, 1942. S K TOWSON ET AL 2,301,832

INDUS TRIAL )BUCK Filed Oct. 30, 1940 6 Sheets-Sheet 5 Fi/'9. 5. SHE D H 7IM/ENTORS L U/V @W50/V BY CLJ/0f f. Cach/,PAN

'ITORNEYS.

NOV. 10, 1942. s. K TOWSON ET AL 2,301,832

INDUSTRIAL TRUCK Filed Oct. 50, 1940 6 Sheets-Sheet 4 Fig. 4.

S/v/fLoa/v 75mm/v BY Qms E. Cac/wn NOV. 10, 1942. 's K, TOWSQN ET AL 2,301,832v

INDUSTRIAL TRUCK Filed oct. 3o, 1940 6 sheets-sheet e 11 Fig. II. Fig. 10o x I INVENTOR5 SHELDo/v l. Tor/salv- BY CMD/ f E. C06/WAN Patented Nov. l0, 1942 UNITED STATES PATENT OFFICE INDUSTRIAL TRUCK Sheldon K. Towson, Cleveland Heights, and Clyde E. Cochran, Cleveland, Ohio, assignors to The Elwell-Parker Electric Company Application October 30, 1940, Serial No. 363,520

2Claims.

This invention relates to industrial trucks and more particularly to the type of truck which is better known as a tilting hoist truck.

Industrial trucks have heretofore been constructed in which different types of motive power are employed to independently operate the var ious functions of the truck. For example, electric motive power may be used for driving the truck, elevating the load or tiltingthe load as the case may be. In some instances either of the latter operations may be accomplished by a hydraulic lift oran arrangement of cables operatedfrom an independently controlled hoisting motor.

Where it is desired however to employ a, gas engine as the centralmotive power for the truck it has heretofore been the practice to convert the automotive power into electrical energy s that the auxiliary hoisting and tilting units could be more easily controlled. It is therefore an object of our present invention to employ a gas engine as the central source of power for an industrial truck and to provide a power transmission `by which the hoisting and-tilting units may be operated directly from the central source of power.

It is a further object of our invention to provide a novel transmission mechanismby which the operation of the hoisting and tilting mechanisms may be independently controlled.

A further object is to provide a novel automatic braking system to sustain the load when the power transmission is disengaged.

Further objects of our invention will become more apparent from the following description given in connection with the accompanying of which:

Fig. 1 is a side elevation of an industrial truck embodying the novel features of our invention;

Fig. 2 is an enlarged plan view of the forward portion of the truck;

Fis. 3 is a sectional view taken through the power transmission unit substantially along the line 3 3 in Fig. 2;

Fig. 4 is a transverse sectional view taken substantially along the line 4-4 in Fig. 3;

Fig. 5 is an end elevation of the clutch control mechanism for the hoisting unit in Fig. 4;

Fig. 6 is an end elevation of the clutch control mechanism for the tilting unit in Fig. 4;

Fig. 'l is a transverse sectional view taken substantially along the line l-l in Fig. 3;

Fig. 8 is a transverse sectional view taken substantially along the line l-I in Fig. 3;

Fig. 9 is a sectional view through the brake unit for the tilting mechanism taken substantially along the line 9-9 in Fig. 3;

Fig. 10 is a sectional view through the brake unit forthe hoisting mechanism taken substantially along the line Ill-I II in Fig. 3;

Fig. 11 is a sectional view taken substantially along the line II-II in Fig. 10;

Fig. 12 is a sectional view illustrating a modified form of brake construction for the hoisting mechanism; and

Fig. 13 is a sectional View taken substantially along the line I3-I3 in Fig. 12.

Referring now to Fig. 1, we have illustrated a conventional type of industrial truck having a chassis comprising a main frame I and an upright auxiliary frame 2 for supporting a power transmission unit. The truck is provided with an automotive engine located generally at 3. Suitable steering mechanism 4 is provided to shift the dirigible wheels of the truck. The power from the engine is transmitted to the wheels of the truck through the usual automotive gear shift transmission 5 to the drive shaft 6. The engagement of the engine with the transmission is controlled by a foot treadle l which actuates a clutch mechanism (not shown) through suitable linkage 8. The operation of the foot treadle l also controls `the braking mechanism' for the truck which is connected thereto through suitable brake linkage 9. The arrangement is such that when the treadle 1 is released by the operator, the

^ linkage 8 automatically disengages the clutch and the brakes are applied through the linkage 9.

The forward end of the truck is provided with the usual hoisting arrangement supported by an upright frame I0. The upright frame III is pivotally supported on trunnions II carried by the main frame I, so that the hoist assembly may be tilted with respect to its vertical position. The tilting of the hoist is accomplished -by a pair of draw bars I2 pivotally connected at I3 to the -hoist frame I0. As illustrated in Figs. 1 and 2 the draw bars I2 are provided with a rack I4 which engages a pinion I5 carried on opposite ends of a cross shaft I6 journalled by suitable bearing members in the frame 2. The hoisting arrangement is also provided with a telescopic extension frame Il and a carriage I9 is slidably mounted within the extension Il. 'Ihe carriage I8 is preferably provided with suitable prongs or tines I9 for supporting a load.

The carriage I8 and the hoist extension Il are elevated in the usual manner by a pair of heavy duty sprocket chains 30 which pass over a series of sheaves positioned on the respective members of the hoist and are attached to the load supporting carriage atv 3|. Each of the chains 30 are driven from sprocket wheels 32 which are ca rried on individual hubs 33 rotatably mounted on a cross shaft 34 supported by the frame member 2. Each of the hubs 33 is driven independently by a pair of sprocket chains 35 passing over a sprocket wheel 38 on each of the hubs and extending over a pair of wheels 31, carried by the cross shaft 38. By this arrangement the load carriage |8 may be raised or lowered independently by each set of chains 30 and 35, in the event that failure of one of the chains should occur.

As illustrated in Fig. 3 the hoisting and tilting of the load are accomplished by a dual transmission, the hoist side of which is generally designated as H and the tilt side as T. Each of the transmission umts H and T is provided with a reversing clutch mechanism generally designated as HI and- Tl respectively, and a self-acting brake unit designated as H2 and T2 for the hoist and tilt units respectively.

The dual transmission units H and T are directly connected to the source of power by a drive shaft 40, as illustrated in Fig. 4. The shaft 40 is preferably connected directly to the crankshaft of the engine 4| and suitable universal joints 42 and 43 may be interposed intermediately of the shaft to accommodate 'any misalignment of the same. The opposite end of the shaft 40 projects into a centrally disposed transmission housing 44 and carries a crown gear 45. The gear 45 is in constant meshing engagement with bevel gears 46 and 41 which are keyed for driving engagement to each of a pair of oppositely disposed shafts 48 and 49 respectively. The shaft 48 is suitably journalled by anti-friction bearing members within the clutch housing 50 of the hoist unit Hi and similarly the shaft 49 is journalled within the clutch housing of the clutch unit TI.

' The clutch reversing mechanism HI for the hoist preferably comprises a pair of oppositely disposed bevel gears 80 and 6| rotatably mounted on the shaft 48 within the housing 50. Each of the gears 80 and 5| are provided with a multiple disc clutch 02 and 83 for independently driving either of the gears 60 or 6| from the shaft 48.

A shiftable sleeve 64 is driven by the shaft 48 and is slidably mounted thereon for axial movement to engage either of the clutch members 62 or 63. The sleeve 84 is adapted to receive a shiftable yoke 65 which is carried by a crank arm IE6, secured toa rotatable shaft 61 journalled in the housing 50. Thus, by rotating the shaft 61 the sleeve 64 may be brought into engagement with either of the clutch members 62 or 63 to thereby independently drive either of the reversing gears GII o'r 6| from the shaft.48.

'I'he positionl of the sleeve 64 with respect to either of the clutch members 82 or 63 is controlled by a star wheel positioned on the shaft 61. In theposition illustrated in Fig. 5 the wheel 10 is held in an intermediate neutral position by a star wheel follower 1|, pivotally mounted on the housing 50. The follower 1| is preferably provided with a. roller 12 for engaging a detent l13 in the wheel 10 where it is yieldably held in engagement by the provision of a spring 14.

The clutch mechanism HI is actuated by a pair of radially extending arms and 16 carried by the star wheel 10. 'I'he arm-15 is connected by suitable fastening means to a flexible cable 80 connected to a control lever 8| in the vicinity it may be seen that when the lever 8| is pushed forwardly to the position indicated as D in Fig. 1, the wheel 10 is rotated to bring the'sleeve 64 into engagement with the clutch 63 as illustrated in Fig. 4 and thereby cause the hoist to move in a downward direction, as Will be hereinafter more fully described. In a similar manner as the lever 8| is pulled back to the position indicated at U in Fig. l, the wheel 10 is rotated inV the opposite direction to engage the clutch 62 and thereby raise the hoist. As the hoist extension I1 reaches the top of its travel it engages a stop lug 82 positioned on a limit rod 83 carried by the frame I0. 'Ihe limit rod 83 is connected by a bell crank lever 84 to a flexible cable 85 the other extremity of which is attached by suitable fastening means to the arm 16 of the wheel 10. Thus, it may be seen that when the hoist extension |1 reaches its upper limit of elevation it trips the limit rod 83 which in turn actuates the wheel 10 to return the clutch sleeve 84 to its normal neutral position. In so doing the control lever 8| is automatically returned to the neutral position indicated by N in Fig. 1.

'Ihe clutch mechanism T| for tilting the hoist frame I0, is operated in a similar manner. The shaft 49 is provided with a pair of oppositely disposed bevel gears 90 and 9| each of which is similarly provided with a multiple plate clutch 92 and 93 respectively. The shaft 49 similarly carries a shiftable sieve 94 which is actuated by a yoke 95 connected through a crank arm 96 and a shaft 91 to a star Wheel 98. A follower 99 and a roller |00 is similarly provided to engage a recess |0| on the wheel 9 8 and thereby establish a neutral position for the clutch sleeve 94. The Wheel 98 is provided with an arm |02 which in turn is connected by the link |03 to the central arm |04 of a bell crank lever pivotally mounted on the housing 5|. As illustrated in Figs. 1 and Gthe bell crank lever is provided with a pair of radially extending arms |05 and |06. The arm |05 is provided with a suitable swivel connection |01 for sli'dable movement on the limit rod |08 which is pivotally connected at |09 to the frame I0. A pair of stop lugs ||0 are positioned on the rod |08 to engage the arm |05 from either direction. Thus it may be seen that when the frame |0 is 'tilted either inwardly or outwardly the stop blocks l0 serve to engage the arm |05 and thereby return the wheel 98 to its neutral position.

The clutch mechanism TI for tilting the hoist is controlled in a similar manner. The arm |08 is connected by a exible cable to a tilt control lever 2 positioned adjacent the operators compartment. In the forward position of the lever I2, as indicated by position I in Fig. 1, the clutch mechanism Tl is actuated to move the y frame I0 inwardly whereas in the position indiof the driver's compartment of the truck, Thus, 75

cated by O, the clutch mechanism is shifted to tilt the hoist outwardly. In a similar manner, when the hoist frame 0 is tilted inwardly or outwardly to its extremity, the limit rod |08 actuates the wheel 98 to return the clutch to its normal position. In so doing the arm |06 acting through the cable returns the operating lever ||2 to its normal position as indicated by the position NI in Fig. 1. Thus, it may be seen that either either the raising of the load or the tilting of the hoist frame may be accomplished from the operators position by the control levers 8| and` I2 respectively and that the extreme position of either of these movements is automatically controlled by the limit rods 83 and |08, to thereby insure safe manipulation of the load.

To transmit power from the clutch shaft 4l to the drive shaft 30 for the hoist, a crown gear |20 is provided for meshing engagement with the reversing bevel gear and 6|. The gear |20 -is preferably carried by a vertically disposed shaft |2| suitably journaled by bearing members in the housing |22 ofthe transmission unit H. As better illustrated in more detail in Fig. 8, the shaft |2| is preferably provided with a worm thread adapted for engagement with a worm wheel |24 carried by the shaft 00. 'Ihus as the clutch sleeve 64 engages either of the bevel gears 60 or 6| for rotation, the shaft Il may be driven in either direction and thereby raise or lower the load carriage i0.

In a similar manner .the tilting transmission unit T is provided with a vertically disposed shaft |25 suitably journaled in the housing |26 and having a crown gear |21 in meshing engagement with the reversing bevel gears 06 and 0|. The shaft |25 is similarly provided with a worm counter-clockwise direction the cam surfaces |46 thread |20 for driving engagement with a worm wheel |29 carried by the cross shaft |50. As illustrated in Fig. 7, the drive shaft |30 is provided with a sprocket wheel lli for driving engagement with a sprocket chain |32 passing over 1 a similar wheel |00 carried by the shaft i6. Thus will climb upon the respective surfaces |45 to thereby force the brake clutch disc |42 away from the spider' |44 and thus apply the braking material |40 to the braking surface of the housing |40. The spider |44 is provided with a pair of radially projecting dogs |41 forengaging a pair of similarly disposed lugs |40, positioned on the disc |42. As illustrated by broken lines in Fig. l0, the rotation of the spider |44 causes the dogs |41 to engage the lugs |48 and drive the disc against the braking surface on thel housing. In this manner the brake is automatically applied whenever the hoist 'clutch HI is released or the load is traveling in a downward direction. As previously described any heat that may be generated by the brake from this reaction is transmitted to the cooling system of the enginethrough the Water jackets 4| provided in the housing |40.

When the load carriage i0 is raised upwardly, the direction of the shaft |2| is reversed and the inclined surfaces 46 of the spider will thereafter slide down upon the inclined surfaces upon actuating the clutch unit Ti for rotationA in either direction the rotation of the shaft |6 will tilt the upright frame i0 of the hoist in either direction with respect to its vertical position.

In the usual operation of the truck a load is picked up by the tines i5 after which the carriage i5 is elevated and the frame |0 is tilted inwardly to stabilize the load before the truck is permitted to advance in a forward direction. In so doing the operator returns the control levers 5| and ||2 to their neutral position which in turn disengages the driving connection between the clutch shafts 40 and 45 and the hoist 40- 'engages when the load is tilted outwardly and is released during the reverse tilting action of the hoist.

The braking unit H2 for the hoist is preferably of the oil immersion type and comprises a casing |40, which is suitably provided with cooling jackets |4| through which the water from the cooling system for the gas engine maybe circulated. The shaft |2| is provided with an extending portion having a brake disc |42 rotatably mounted thereon. 'Ihe disc |42 is provided with suitable friction material |43 for engaging a flat braking surface formed in the housing |40. A spider |44 is carried by the shaft |2| for the purpose of engaging or disengaging the brake disc |42 and apply the brake when the load carriage il is moving in a downward direction.

As illustrated in more detail in Figs. 10 and 1l the brake disc |42 is preferably provided with a series of inclined camming surfaces |45 spaced radially of the shaft |2|. The adjacent face of the spider |44 is provided with a series of oppositeLv disposed inclined camming surfaces |46 y 4which are positioned in opposing relationship to of the brake disc and thus relieve the axial thrust of the brake material upon the housing. y

`In Figs. 12 and 13 we have shown a modified form of brake construction for the hoist which may be embodied in a housing |50, similar to that described with reference to Fig. 3. A brake disc |5| is rotatably mounted upon the shaft |2| and is provided with suitable brake friction material |52. The disc |5| is preferably provided with a hollow brake drum |53 which rotatably embraces a hub |54 carried by the shaft |2 l. To engage the brake drum |53 the hub |54 is provided at its circumference with a series of inclined recesses |55 extending axially of the hub. These recesses are provided with a series of rollers |56 yieldably held in contact with the drum by means of recessed spring members |51. 'I'hus when the shaft |2| is rotated in a direction to lower the carriage i0, the rollers |56 become wedged between the surfaces |55 and the drum |50 and thereby rotate the brake disc |5| to pro'- vide a self-acting brake to the downward movement of the load. On the other hand when the shaft |2| is rotated in the opposite direction the rollers |56 are free from engagement with the brake drum |53 and hence release rotation of the brake disc |5I.

As illustrated in Fig. 9 the brake unit T2 for restraining the outward tilting movement of the hoist comprises a brake drum |60 carried by the shaft |25. The brake mechanism preferably comprises a flexible band |6| having suitable.

friction material |62 secured to its inner surface adjacent the drum. The band |6| is secured at one end to a stationary pivotal point |63, carried by the casing. 'I'he other end of the band is yieldably secured by an adjustable spring member |64 to a recessed portion of the casing. Hence it may be seen that when the drum |60 is rotated to tilt the hoist outwardly, the band |62 will wrap upon the drum |60 and apply a braking action to the shaft |25. Similarly when the rotation of the drum |60 is reversed, the yieldable action of the spring |64 will tend to unwrap the band |62 from the drum and thereby release the braking action.

It may therefore be seen that we have invented a new and novel transmission for an industrial truck which may be operated from a central source of power such asan automotive engine to either independently drive the truck, hoist or tilt the load. It is further apparent that each of the foregoing operating units are provided with automatic self-acting brakes so that the loads may be maintained in any position and the truck abandoned by the operator without danger.

We claim:

1. A power transmission for an industrial truck comprising a power drive shaft, a pair of driven auxiliary shafts and a clutch reversing mechanism for disconnecting or reversing the direction of rotation of each of the auxiliary shafts.4 a power take-olf for one of the auxiliary shafts including mechanism adapted to raise or lower a hoist and a power take-oi! for the other shaft including mechanism forA tilting the hoist in either direction from its vertical position and one way self-acting braking means carried by each of the auxiliary shafts which become active to resist the turning of the respective shafts when the latter are rotated in a direction to lower the hoist or t0 move the same outwardly from the truck respectively.

2. In an industrial truck having mechanism for tilting and elevating a load lifting hoist, a power transmission comprising a housing, a central driveeshaft and a pair of oppositely disposed auxiliary drive shafts operatively connected to the central shaft, a pair of oppositely disposed reversing gears carried by each of the auxiliary shafts and a clutch associated with each of said gears, a shiftable clutch member for actuating either of the reversing gears, a speed reduction mechanism adapted to be driven by either of the reversing gears on one of the auxiliary shafts and a. second reduction unit similarly connected to the other auxiliary shaft, a power take-olf for `each of the speed reduction units, means for con- SHELDON K. TOWSON. CLYDE E. COCHRAN. 

